Abstract: Numerical simulations of a plasma jet ignition process and a gasoline/air two-phase detonation process considering chemical reaction mechanism in a pulse detonation engine are carried out by the method of conservation element and solution element (CE/SE). The effects of different plasma jet energy and jet time on the detonation process are discussed. The results show that the deflagration to detonation transition (DDT) time and DDT distance can be shortened by increasing plasma jet energy. When gasoline/air mixture was fully lit in jet areas, plasma jet time does not affect the DDT process. The calculation results are in good agreement with experimental ones. The research work provides a theoretical guidance for the optimal design of PDE ignition structures.